• 대한교통학회지
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• 제19권2호
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• pp.21-28
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• 2001

본 연구는 다양한 좌회전 곡선반경을 갖고 있는 교차로에서의 좌회전 포화교통류율의 분석을 통하여 좌회전의 직진환산계수를 산정하는 것이다. 한국 도로 용량편람에서는 곡선반경이 약 20m 이상인 곳에서는 좌회전 전용차로에 대하여 직진과 같은 포화교통류율을 보이는 것으로 조사되어 좌회전 보정계수는 없는 것으로 제안하고 있다. 하지만 KHCM은 간선도로 위주로 조사 분석되어 곡선반경이 20m 이하인 교차로가 제외되어 있다. 이에 본 연구에서는 좌회전 전용차로 1개를 갖고 곡선반경이 20m 이하인 교차로 포함하여 다양한 곡선반경 가진 교차로를 대상으로 연구를 수행하였다. 본 연구에서는 포화교통류율을 산출하는데 있어서 분산분석의 후속단계인 다중비교(Multiple comparison)방법중 던컨검정(Duncan's Test)을 이용하였다. 본 연구에서 산정된 좌회전의 직진환산계수는 도로용량편람에서 교차로 분석시 교차로 곡선반경을 반영한 정확한 포화교통류율을 산정할 수 있다. 본 연구의 결과는 좌회전 곡선반경 20m 미만 교차로에서의 좌회전 S는 직진포화교통류율 보다 낮게 결과가 나타났다. 이를 직진환산계수화 시키면 좌회전 곡선반경에 따라서 1.05에서 1.14사이다.

• 한국철도학회논문집
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• 제6권4호
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• pp.246-251
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• 2003

A quantitative analysis on the amounts of cant and lateral displacement of gravitational center due to the introduction of high-speed tilting car was carried out, based on the current alignment of the conventional line. In addition, the maximum allowable speed in curve and the level of improvement in maximum speed of tilting car were evaluated through the comparison with the maximum speed of locomotive. It was found that the tilting car produces an equivalent amount of cant, which corresponds to 47.5 % of current actual cant. This effect could be explained by the fact that 1.34 m, which is the height of gravitational center of tilting car from the rail level, is much lower than that of locomotive and thus guarantees much higher level of safety in curve. The equivalent amount of cant due to the lateral displacement of gravitational center followed by tilting in curve was 2.4 mm. It was small but not enough to be neglected and must be included in calculating the maximum speed in curve. It could be concluded that the 15 % speed-up of the conventional line is reasonable under the current condition of alignment.

• 전력전자학회:학술대회논문집
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• 전력전자학회 1999년도 전력전자학술대회 논문집
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• pp.282-286
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• 1999

This paper presents a vector control of parallel drive, a beatless control and a low switching PWM technique for the propulsion system of Electric car as transient state which are included interrupting line voltage, changing line voltage slowly, suddenly, regenerating light load and starting from backward running. Improved performance and a validation of proposed method is shown by the experimental results using a 1.65MVA IGBT VVVF inverter and inertia load equivalent to 160 tons electric cars through a running and transient state test.

• 한국철도학회:학술대회논문집
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• 한국철도학회 1998년도 추계학술대회 논문집
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• pp.345-352
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• 1998

The dynamic analysis of a train system has tended to analyze one vehicle or subsystem of that rather than to analyze entire vehicles. But, the speeding and lightening of a train requires more accurate analysis. Thus, the analysis of entire vehicles is required but it spends much time. Therefore, it is needed to find out the new analytic method which is more accurate and efficient. This paper suggests a new method for analyzing a multi-vehicle system more efficiently, using‘mechanical impedance’At first, get the impedance of vehicles which influence the dynamics of the object car, through analyzing the dynamics of a vehicle. ‘Equivalent system’, a simple mechanical system, of which the impedance is similar to that ,is proposed. Then, the equivalent system was applied to a vehicle and it showed that the equivalent system works like a real vehicle system. Finally, we tried non-linear analysis of a vehicle to which the equivalent system is applied.

• 한국도로학회논문집
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• 제17권3호
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• pp.97-105
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• 2015

PURPOSES : The Toll Collection System (TCS) operated by the Korea Expressway Corporation provides accurate traffic counts between tollgates within the expressway network under the closed-type toll collection system. However, although origin-destination (OD) matrices for a travel demand model can be constructed using these traffic counts, these matrices cannot be directly applied because it is technically difficult to determine appropriate passenger car equivalent (PCE) values for the vehicle types used in TCS. Therefore, this study was initiated to systematically determine the appropriate PCE values of TCS vehicle types for the travel demand model. METHODS : To search for the appropriate PCE values of TCS vehicle types, a traffic demand model based on TCS-based OD matrices and the expressway network was developed. Using the traffic demand model and a genetic algorithm, the appropriate PCE values were optimized through an approach that minimizes errors between actual link counts and estimated link volumes. RESULTS : As a result of the optimization, the optimal PCE values of TCS vehicle types 1 and 5 were determined to be 1 and 3.7, respectively. Those of TCS vehicle types 2 through 4 are found in the manual for the preliminary feasibility study. CONCLUSIONS : Based on the given vehicle delay functions and network properties (i.e., speeds and capacities), the travel demand model with the optimized PCE values produced a MAPE value of 37.7%, RMSE value of 17124.14, and correlation coefficient of 0.9506. Conclusively, the optimized PCE values were revealed to produce estimates of expressway link volumes sufficiently close to actual link counts.

• 한국기계가공학회지
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• 제14권2호
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• pp.44-50
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• 2015

This study investigated the durability of the under bar of a car through structural and fatigue analysis. Model 1 had the lowest value among three kinds of models. In the case of the maximum equivalent stress and displacement at structural analysis, model 1 showed the highest durability. Also, models 3 and 2 showed structural durability in order of this value. In the case of fatigue analysis, the maximum fatigue lives of the three models were equal to $2{\times}10^7$cycles. However, model 1 showed the highest value among the three models, as the minimum fatigue life of model 1 becames 92.56 cycles. Also models 3 and 2 showed fatigue durability in order of this value. The maximum possibility of fatigue damage for models1,2,and 3 became 30%. If the results of this study are applied to change the design shape of the under bar of cars, the ride comfort for automobile passengers and car durability can be improved.

• 한국기계가공학회지
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• 제17권3호
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• pp.28-33
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• 2018

The automotive front bumper guard is the most important part of the vehicle for protecting the life of driver when a traffic accident happens. In order to ensure safe driving, this part must possess sufficient strength and durability. This study was carried out with structural and fatigue analyses by designing front bumper guard models. After the lowest value for maximum total deformation and equivalent stress was found through structural analysis and the highest value for fatigue life was found for all three models, it was shown that the type C front bumper guard model was the most suitable for application to a real car. The strength property and durability of the optimum design were determined through this study's results.

• 한국융합학회논문지
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• 제10권7호
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• pp.149-154
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• 2019

본 논문은 오프로드용 SUV 자동차의 프론트 언더커버에 대한 구조해석을 통하여 내구성을 연구하고자 한다. 실제 사용되는 차체 하부 보호용 언더커버의 형상과 비슷한 3종류의 모델들을 해석하여 어떤 모델이 구조적으로 가장 좋은 것인지 고찰하였다. 언더커버의 모델들은 CATIA 프로그램을 통하여 Model A, B, C 3종류로 설계하였고 ANSYS 프로그램을 이용하여 해석을 하였다. 해석 결과들을 통하여 세 모델들 중에서 Model B가 최대 등가 응력이 가장 작고 피로 수명도 길어서 내구성이 가장 좋은 것으로 나타났다. 본 연구결과를 토대로 얻은 언더커버의 내구성 있는 설계데이터를 활용함으로서 실생활에서의 기계나 구조물에 융합하여 그 미적 감각을 나타낼 수 있다.

• 한국자동차공학회논문집
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• 제24권5호
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• pp.504-511
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• 2016

This study investigates the durability of strut bar at car through structural and fatigue analyses. In this study, there are model 1 and model 2 as the analysis subjects. Model 1 is the existed one and model 2 is the improved one added with the reinforced part. Model 1 has the maximum equivalent stress of 165.11 MPa shown intensively at the welding part between the bracket and the bar. This stress is distributed over at the part of model 2 reinforced with this part. In case of fatigue analysis, there are three kinds of fatigue load as SAE bracket history, SAE transmission and sample history. The maximum fatigue life at SAE bracket history among three kinds of fatigue loads has the least value of $3.3693{\times}10^5$ cycles. The maximum fatigue life of model 2 becomes longer than that of model 1. As model 2 has the fatigue damage less than model 1, model 2 has the safety than model 1. As the fatigue durability about the configuration of strut bar is analyzed, it is thought to apply this study result into the real part effectively.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2008년도 추계학술대회 논문집
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• pp.1776-1781
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• 2008

To reduce interior noise of running vehicles, a floating floor construction has been widely used in recent railway industry. Among the key factors of the floating floor design, dynamic stiffness is of most important in acoustical point of view. Sometimes hard rubber type supports have often been selected due to the other design constraints such as heavy load condition, durability of rubber element and its cost etc., even though it seems like the softer support, the better isolation of noise and vibration. In this paper two representative floor supports have been considered to evaluate their effectiveness in interior noise contribution: one is a soft rubber and another is a relatively hard one. From the measured dynamic stiffness of the specimens, equivalent stiffness of actual floating floor has been derived to use in the analytical models. Calculated air-borne and structure-borne noise insulation properties of the floating floors have been compared with experiments in prototype car. In full car model interior noise levels of running vehicles have been predicted to quantify the effectiveness of the two different floating support materials and verified through the measured inside noise levels of actual train as well. By comparison with difference of running noise levels two materials for floor support can be investigated quantitatively so that it could be applied in floating floor design.